In the production of vacuum interrupters, in the final phase of the production process, a certain number of individual parts and assemblies have to be joined together to form a complete unit. The housing thereby formed has to be evacuated and sealed in a vacuumtight manner. To reduce the use of soldering forms when joining together the individual parts and assemblies and the subsequent soldering process, or to be able to dispense entirely with such soldering forms, it is known to assign individual parts to one another in a self-centering manner. In the case of vacuum interrupters with a hollow-cylindrical ceramic insulator and two end caps made of high-grade steel as housing parts, it may be envisaged, for example, to connect the end caps to the ceramic insulator by means of end-on soldering with a compensating layer of copper interposed. For the self-entering of the parts which are to be connected, it is typical to form the compensating layer in one piece with a control shield covering the inner edge of the ceramic insulator and to provide the parts both with a first centering portion, which bears against the inner surface of the ceramic insulator, and with a second centering portion, which centers the end cap. The first centering portion may in this case be formed by peripherally arranged projections which are elastically resilient in the inward direction and, for this purpose, are formed as bosses and are surrounded by a horseshoe-shaped punched clearance. The second centering portion is formed by an annular centering lug (See, for example, DE 36 28 174 A1). A known variant of this configuration envisages use of the bosses in the peripheral direction of the control shield tabs that are made to protrude (See, for example, DE 39 31 774 A 1). Such centering elements may also be used in the case of vacuum interrupts with two ceramic insulators arranged coaxially one behind the other, to achieve for a shielding held in the joining region of these insulators a self-centering effect in this area. Alternatively, this is also possible with a holding part in the form of an annular disk, which for connection to the shielding merges with a tubular lug and is provided in the disk-shaped region with tabs made to protrude in the axial direction, which are pressed out alternately in one direction and in the other direction (See, for example, DE 37 19 256 A1).
In the case of vacuum interrupters in which no control shield in the end region of the ceramic insulator or any shielding is required, the compensating layer of copper in the form of an annular disk may also be provided with inner tabs for centering the annular disk on the inner side of the ceramic insulator and with outer tabs for centering the end cap (cover) (See, for example, DE 87 09 569 U1).
It is further known in the case of vacuum interrupters in which metal housing parts are connected to ceramic insulators without the use of a compensating layer by means of blade soldering, to couple the self-centering measures with the soldering process in such a way that the soldering foil itself serves as the centering means. In this case, the soldering process may be devices as seal-soldering (See, for example, DE 197 53 031).
In order to simplify, in the case of vacuum interrupters, the soldering technique for connecting ceramic parts to copper parts, in particular so-called blade soldering, but also the connection of copper parts to one another or to other metal parts, it is further known to use copper parts which are provided with a silver layer both in the area of the actual connecting location and in areas adjoining that, if appropriate as a complete unit. At a soldering temperature of around 800° C., this silver layer forms with the surface layer of the copper part a eutectic connection, which at the same time represents the soldering material. In this way it is possible for example to connect a copper housing cap simultaneously and in a vacuumtight manner to a ceramic insulator and in an adhesively/cohesively bonded manner to a shielding ring (See, for example, DE 43 20 910 C1).
Starting from a connection area between two housing parts of a vacuum interrupter assigned coaxially to each other, in which one housing part is a hollow-cylindrical ceramic insulator which is connected at the end face to the outer housing part and in which an annular disk-like centering means placed onto the ceramic insulator and provided with centering lugs is arranged between the two housing parts, the invention is based on the object of optimizing the connection area with regard to the complexity of production for centering measures and with regard to the execution of the soldering process.